Three in 10 children read daily in their own time, down from four in 10 in 2005, the study found. Photograph: Alamy

The proportion of children reading for pleasure has declined as their time is crowded with other activities, and more than a fifth never read in their own time, according to research published on Friday.

The study, which finds a clear link between reading outside class and high achievement in school, reveals that fewer children are reading comics and magazines.

The research by the National Literacy Trust was based on a study of more than 21,000 children carried out last year.

It finds that text messages are the most commonly read material outside of class.

The proportion of children reading magazines has declined from over three-quarters in 2005 to 57% last year.

When the survey was first conducted in 2005, four in 10 children said they read daily in their own time. That figure is now around three in ten.

The research found that young people were shunning books in favour of TV – 54% of those questioned said they preferred watching TV to reading.

The National Literacy Trust’s director Jonathan Douglas said: “The fact that children are reading less than in 2005 signals a worrying shift in young people’s literacy habits.

“We are calling for the government to back a campaign to halt this reading decline and to give children time to read in their daily lives.”

A Department for Education spokesman said: “The findings of this survey come as no surprise and show that we need to continue our drive to encourage young people to develop a love of reading. In a world of so many distractions for young minds, the place of literature is more important than ever.”